Darwin's great insight—that life has evolved over millions of years by natural selection—has been the cornerstone of all of David Attenborough's natural history series. In this documentary, he takes us on a deeply personal journey, which reflects his own life and the way he came to understand Darwin's theory. By visiting Darwin's home and tracing the voyage of the Beagle across the world, Attenborough explains how the naturalist revolutionized our understanding of the natural world. New wildlife footage of fascinating animal behavior brings the theory to life, and fresh evidence and new discoveries reveal how Darwin's work has been endorsed and expanded upon by today's cutting-edge science.